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Chlorine Solution Ph Adjustment for Disinfection
How & why to check & adjust the pH of disinfectant solutions for wells & water treatment equipment
- POST a QUESTION or COMMENT about this article topic.
Chlorine solution pH test & adjustment when treating drinking water:
Making sure that a chlorine disinfectant solution used to shock a water well or to disinfect building water piping or water treatment equipment can help determine a successful outcome.
This article defines pH - the acidity or basic or neutral property of a liquid, and explains how to test and adjust the pH of a solution as needed when disinfecting a water supply system.
Well disinfection, shocking, & restoration procedures recommended by the BC Canada Ministry of Health & other expert sources include helpful details that can increase the chances that the disinfection is successful, producing potable water.
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Importance of adjusting the pH of Well Water & Well disinfectant Solution
Many experts have discussed the effect of solution pH on the effectiveness of disinfection, including the disinfection of wells and water treatment equipment. Dailloux (1999) for example, points out that certain nontuberculous mycobacteria include resistant strains that tolerate low pH and high temperatures, while other sources point out that high pH is an equally serious concern. (Yu-sen 2002).
And as we cite below, health professionals writing about optimum well disinfection procedures have elaborated the importance checking and adjusting the pH of water and disinfectant solutions.
Explanation of pH levels: the pH (power of hydrogen) of any liquid solution is a measure of how acidic or how basic the solution is. Low pH = acidic. High pH = basic. Solutions with a pH over 7 are considered basic or alkaline while solutions with a pH under 7 are considered acidic. A solution with a pH close to 7 is essentially neutral.
Lemon juice or vinegar and some soft drinks such as Coke® are common household acids; ammonia (NH3) is a common weak base while household bleach is very alkaline - a strong base.
What this means to a non-scientist is that when attempting to disinfect a well or water treatment equipment, taking the time to check and if necessary adjust the pH of a solution can make the difference between a successful disinfection and a failure. Essentially we want a neutral pH or a pH in the range of 6-7 by some sources or pH of 7-7 by others (Hua 2002).
Reader Mark has encountered and discussed the importance of pH (and also well casing deposits) when chlorinating a water well. Mark posted as a comments on 3/22/2013 & 1/31/2014Bacteria can hide behind surface rust/debris on well casings. Taking two different samples, one from the casing and one from the aquifer should identify this situation: google this procedure; basically for casing samples you figure how much time it takes to pump the water in your discharge pipe out and add a minute to it, pump and take sample; for the aquifer sample you have to do the same basic procedure, but with figuring the amount of water in the well casing (no problem running well beyond such time, assuming that you're not risking running dry).
I've got a 35' well (been out of use for a good ten years, no real history, was left open) that I'll be rehabbing shortly. One of the things that I'll be doing is running a casing brush (WireHog) to clean the casing. I'll also be blowing out the well casing to make sure that there's not a bunch of crud in there.
Upon completion of this cleaning I will shock by back-flushing about 500 gallons of "treatment" (sodium hypochlorite and water) based on the optimal mixture ratio.
Watch out: if you use too strong a disinfectant solution you may not kill the bacteria: you end up increasing the pH level and defeating the biocidal capacity of the sodium hypochlorite, not to mention potential damage from increased pH levels on the casing, pumps and screens: test the pH and adjust with vinegar
I was ignorant of all of this and just dumped a gallon of bleach down the well. Clearly this didn't rectify my problem (and I now know why this might be so). The Alberta Agriculture and Rural Development has an excellent online page on Shock Chlorination [citation given in this article - Ed.].
Mark continued on 1/31/2014
Actually, one of the best places for bacteria to live is in the static to draw-down area.
I should have also stated that slime-forming bacteria can hide the real nasty stuff (coliform and e-coli). And the slime can inhabit all down the casing, the screens and out in to the aquifer. According to Well folks it can be necessary to brush out a well in order to achieve a good kill on the bacteria.
Again, pH IS EXTREMELY IMPORTANT! [The writer's reference citation from the Canadian BC Ministry of Environments given at the end of this section]
In general, they adjust water in a tank to a pH of 4.5 and THEN add chlorine. I wasn't aware of this procedure until after I mixed up my solution. Now that I have an actual personal experience in this I think that I can comment on it... I mixed up a 200ppm sodium hypochlorite solution (8.25% Clorox) in 275 gallons of pH neutral water (my spring water is nearly dead-on, 6.8 - 7.0 pH). I had ASSUMED, based on all the casual experts comments (in addition to information from various water publications [people that actually should be responsible]), that I shouldn't be too far off pH-wise- WRONG! I'm over 8.4 pH!
If you read the [BC health ministry document cited & linked below] you'll find that having a pH value that is much beyond neutral won't be effective as a biocidal. All of this should tell folks why they have difficulties really getting the job done and then have to end up shelling out a lot of money to pay a professional.
I am now trying to adjust the pH down... (don't have a lot of time before I lose the chlorine efficacy). Yes, there is a reason why the good professional well folks should earn what they do.
Reply:
Re: Mark's 2013 comment
Excellent points Mark - which explains why it can be difficult to sanitize a well, but ONLY if there is actual exfoliating rust inside the well casing - which is not usually the case. Normal surface rust is not a substantive block to disinfectants used in a well. But a thick mineral deposit that may build up in some wells (in the area of the casing or well borehole that is normally water-filled) can make disinfection more difficult in those wells unless disinfection is accompanied by mechanical cleaning.
We agree that what is important is using a proper strength of disinfectant, for an adequate time, followed by through flushing of the well and after a suitable wait time, a follow-up test.
The well sanitizing procedures we document at InspectApedia cite U.S. & Canadian federal and state expert sources & health departments - those are the most expert people we can find.
Mark's 2014 comment was in regards to mine:
"it can be difficult to sanitize a well, but ONLY if there is actual exfoliating rust inside the well casing - which is not usually the case. Normal surface rust is not a substantive block to disinfectants used in a well."
We agree completely.Just below for reader convenience and also at References [5] we have cited and link to a PDF file copy of the helpful BC ministry document to which Mark refers.
My original comment was directed at typical residential well disinfection and
the PROCEDURE & QUANTITY of BLEACH NEEDED to SHOCK A WELL - and did not adequately focus on on pH adjustment and on disinfecting a well contaminated by area flooding - a more extreme situation that may have forced floodwaters into the aquifer itself.
For a detailed procedure for disinfecting a well after area flooding see this helpful document cited both in our references and again just below:
"When Standard Water Well Chlorination Procedures are Ineffective: fact Sheet developed for Well Drillers, Health Authority Staff and others involved in well recovery efforts after a flood " [PDF] - British Columbia Ministry of Environment, retrieved 1/31/2014, original source: http://www.env.gov.bc.ca/wsd/ plan_protect_sustain/groundwater/ wells/factsheets/PFRA_well_recovery.pdf
In addition to the pH problem in disinfecting flooded wells, I add Manci's caution about giardia:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- References [3]
The document from the BC ministry makes a sound point that it can be difficult to disinfect a water well following a flood, giving two reasons why well disinfection may be unsuccessful.
- The groundwater may still be contaminated with flood water or there may be a source of continuing contamination.
- The well was infrequently (or never) cleaned prior to the flood, and over time large quantities of mineral scale and biofilm have accumulated in the well. This material can greatly impair attempts to disinfect a well.
pH Test Kits - litmus paper in rolls or strips read water or disinfectant solution pH level
Simple litmus paper (made from paper and dyes extracted from lichens) test strips can be used to test water for its pH level: acids turn litmus paper pink while bases turn litmus paper blue.
You can purchase pH test kits and strips at drug stores, swimming pool suppliers, test equipment suppliers, some plumbing suppliers, and of course, online.
- Hydrion pH test strips, include a simple color scale that gives pH readings between 0 (acidic) and 13 (basic) - www.microessentialslab.com
- pHion Balance Diagnostic pH Test Strips, produced by pHion balance
- pH-Strips, Enzymedica
How to Adjust Water & Disinfectant pH when Shocking a Well
Adapted from "When Standard Water Well Chlorination Procedures are Ineffective:... " [PDF] - British Columbia Ministry of Environment, retrieved 1/31/2014, original source: http://www.env.gov.bc.ca/wsd/ plan_protect_sustain/groundwater/ wells/factsheets/PFRA_well_recovery.pdf
Fresh potable water in the mixing tank to be used for preparing the disinfectant solution to be injected into the water well should be tested for pH level.
The target pH for fresh potable water intended for disinfection is 4.5 (before adding chlorine) - this is equivalent to a weak acid solution.
Before adding the chlorine solution, you can lower the pH of water by adding a safe weak acid such as household vinegar (acetic acid). Depending on the observed pH you may need to add 20 as much as Liters of 5% acetic acid (household vinegar) to 1000 Liters of water. Slowly add the acetic acid to the water while stirring the tank and then check the pH again as needed until you've reached the target pH.
Watch out: the pH of the water supply plays an important role in the corrosion of copper and brass piping and plumbing fittings or parts.
See DEZINCIFICATION vs WATER SUPPLY pH
How to Add the Chlorine (household bleach, sodium hypochlorite) to the Water to Prepare Well Disinfectant
When the water is at the proper pH, add the required amount of chlorine -
see WELL DISINFECTANT TABLE, POST FLOODING for the quantity of bleach you will need.
Lower the pH of the water in the mixing tank to a pH of 4.5 before adding the chlorine; a weak acid like vinegar (i.e. 5% acetic acid) can be used for small well applications since it is readily available and fairly safe to use (20 L of 5% acetic acid may be required for every 1000 L of water added to the well).
Watch out: the Canadian Ministry of Environment warns in the source document that because we are adding chlorine to a weak acid (pH 4.5) some chlorine gas will form. Chlorine gas can be harmful or even fatal at high concentrations and exposures. The ministry recommends:
To lower the pH in the mixing tank, slowly add the acid to the water while checking the pH level with pH test strips. Agitate the water to ensure uniform distribution of the acid.
Always prepare the chlorine solution outside in a well-ventilated area and stand up-wind when adding the chlorine to the acid solution.
Watch outfor hydrogen sulfide (H2S - which produces a rotten egg or sulphur smell) in the water. This gas is not just smelly, it can be dangerous, a health risk and een an explosive. If there is H2S in the water you will need to aerate the water to dissipate that gas before adding vinegar (or chlorine) to the water.
See CHLORINE SAFETY WARNING where we discuss both H2S and chlorine gas hazards.
The advice continues to explain that while some chlorine gas will form at pH 4.5 (you'll smell it), the addition of the chlorine raises the pH to a safe level - that is, the total quantity and duration of chlorine gas formation should be low. As you add chlorine the solution becomes alkaline.
Check the disinfectant solution pH again.
When ready for use, the disinfectant solution (water + chlorine) should have a pH between 6 and 7 to be most effective as a biocide.
Step by step well disinfection procedures using pH adjusted disinfectant solution are given in these two articles:
Chlorine & Well or Water Equipment Disinfection Solution pH Adjustment & Target References
- OurReferences or Citations for this article contain a complete list of citations; excerpts are shown just below
- Ascenzi, Joseph M., ed. Handbook of disinfectants and antiseptics. CRC Press, 1995.
- Bassett, D. C. J. "The effect of pH on the multiplication of a pseudomonad in chlorhexidine and cetrimide." Journal of clinical pathology 24, no. 8 (1971): 708.
- Brodtmann Jr, Noel V., and Peter J. Russo. "The use of chloramine for reduction of trihalomethanes and disinfection of drinking water." Journal (American Water Works Association) (1979): 40-42.
- Dailloux, M., C. Laurain, M. Weber, and P. H. Hartemann. "Water and nontuberculous mycobacteria." Water Research 33, no. 10 (1999): 2219-2228.
- Fair, Gordon M., J. Carrell Morris, Shih Lu Chang, Ira Weil, and Robert P. Burden. "The behavior of chlorine as a water disinfectant." Journal (American Water Works Association) 40, no. 10 (1948): 1051-1061.
- Hua, Guanghui, and David A. Reckhow. "Comparison of disinfection byproduct formation from chlorine and alternative disinfectants." Water Research 41, no. 8 (2007): 1667-1678.
- Richardson, S. D., A. D. Thruston Jr, T. V. Caughran, P. H. Chen, T. W. Collette, K. M. Schenck, B. W. Lykins Jr, Ch Rav-Acha, and V. Glezer. "Identification of new drinking water disinfection by-products from ozone, chlorine dioxide, chloramine, and chlorine." In Environmental Challenges, pp. 95-102. Springer Netherlands, 2000.
- Waltimo, T. M. T., D. Ørstavik, E. K. Siren, and M. P. P. Haapasalo. "In vitro susceptibility of Candida albicans to four disinfectants and their combinations." International Endodontic Journal 32, no. 6 (1999): 421-429.
- Ward, N. ROBERT, R. L. Wolfe, and BETTY H. Olson. "Effect of pH, application technique, and chlorine-to-nitrogen ratio on disinfectant activity of inorganic chloramines with pure culture bacteria." Applied and environmental microbiology 48, no. 3 (1984): 508-514.
- Wu, Wells W., Paul A. Chadik, William M. Davis, Joseph J. Delfino, and David H. Powell. "The effect of structural characteristics of humic substances on disinfection by-product formation in chlorination." In ACS SYMPOSIUM SERIES, vol. 761, pp. 109-121. Washington, DC; American Chemical Society; 1999, 2000.
- Yu-sen, E. Lin, Radisav D. Vidic, Janet E. Stout, and L. Yu Victor. "Negative effect of high pH on biocidal efficacy of copper and silver ions in controlling Legionella pneumophila." Applied and environmental microbiology 68, no. 6 (2002): 2711-2715.
...
Reader Comments, Questions & Answers About The Article Above
Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
Reader Q&A - also see RECOMMENDED ARTICLES & FAQs
Question/Comment: well contaminating bacteria may hide in a slime layer in the draw-down section of the well casing. Attending to water pH is very important when sanitizing a well.
In an earlier response to Mark (Mod) said (with details added here)
"Regarding your comment (posted at WELL CHLORINATION & DISINFECTION) that bacteria hide in the steel well casing, it can be difficult to sanitize a well, but from the well casing, principally if there is actual exfoliating rust inside the well casing - which is not usually the case.
Normal surface rust is not a substantive block to disinfectants used in a well. Indeed good well shocking procedure recycles treated sanitizing water from an outdoor hose hook-up to a garden hose (themselves hardly sanitary) used to wash-down the entire well casing interior surface. "
Mark Comments Further:
Actually, one of the best places for bacteria to live is in the static to draw-down area.
I should have also stated that slime-forming bacteria can hide the real nasty stuff (coliform and e-coli). And the slime can inhabit all down the casing, the screens and out in to the aquifer. According to Well folks it can be necessary to brush out a well in order to achieve a good kill on the bacteria.
Again, pH [of the well water] is extremely important! Here, read this (from the great water folks up in Canada) - BC Ministry of Environment, "Water Stewardship Information Series: When Standard Water Well Chlorination Procedures are Ineffective
Fact Sheet developed for Well Drillers, Health Authority Staff and others involved
in well recovery efforts after a flood"[5] Quoting:
Experience has shown that standard chlorination procedures are not always effective in disinfecting water wells, and well owners can continue to experience unsatisfactory coliform test results following chlorination. There can be several reasons for this:
- The groundwater may still be contaminated with flood water or there may be a source of continuing contamination.
- The well was infrequently (or never) cleaned prior to the flood, and over time large quantities of mineral scale and biofilm have accumulated in the well. This material can greatly impair attempts to disinfect a well.
It is recommended that a registered water well contractor and/or a registered pump installer be used to carry out the work described in this fact sheet. [5]
If a well owner finds that, following chlorination, they continue to get unsatisfactory coliform test results, they may need to bring in a registered water well driller or registered pump installer to carry out more aggressive cleaning and disinfection of their water well.
To disinfect a water well that has not received regular preventative treatments, it is recommended that the well be thoroughly cleaned using mechanical and chemical procedures and then disinfected using a pH adjusted chlorine solution. [5]
[This article describes the formation of both biofilm and mineral deposits that accumulate inside a water well over time, and argues for using a pH-adjusted chlorine solution to the well to increase the biocidal effectiveness of the disinfectant. - Ed.]
Liquid chlorine or granular chlorine is extremely alkaline, resulting in an increase in pH when mixed with water. As more chlorine is added, the pH rises and the chlorine becomes more oxidative in nature. In a high oxidative state, chlorine can corrode metals, produce chlorine gas, and is slow to kill bacteria. For optimum disinfection it is important to keep the concentration of chlorine below 200 ppm and maintain a fairly neutral pH. [5]
In general, they adjust water in a tank to a pH of 4.5 and THEN add chlorine. I wasn't aware of this procedure until after I mixed up my solution. Now that I have an actual personal experience in this I think that I can comment on it... I mixed up a 200ppm sodium hypochlorite solution (8.25% Clorox) in 275 gallons of pH neutral water (my spring water is nearly dead-on, 6.8 - 7.0 pH). I had ASSUMED, based on all the casual experts comments (in addition to information from various water publications [people that actually should be responsible]), that I shouldn't be too far off pH-wise- WRONG! I'm over 8.4 pH!
If you read the above document you'll find that having a pH value that is much beyond neutral won't be effective as a biocidal. All of this should tell folks why they have difficulties really getting the job done and then have to end up shelling out a lot of money to pay a professional.
I am now trying to adjust the pH down... (don't have a lot of time before I lose the chlorine efficacy). Yes, there IS a reason why the good professional Well folks should earn what they do.
Reply:
Thanks Mark, important details to add both about the algae or bacterial slime that might be present in some well casings, depending on water chemistry, as well as the importance of well water pH.
...
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CHLORINATION WELL SHOCKING PROCEDURE
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Citations & References
In addition to any citations in the article above, a full list is available on request.
- Ascenzi, Joseph M., ed. Handbook of disinfectants and antiseptics. CRC Press, 1995.
- Bassett, D. C. J. "The effect of pH on the multiplication of a pseudomonad in chlorhexidine and cetrimide." Journal of clinical pathology 24, no. 8 (1971): 708.
- Brodtmann Jr, Noel V., and Peter J. Russo. "The use of chloramine for reduction of trihalomethanes and disinfection of drinking water." Journal (American Water Works Association) (1979): 40-42.
- Dailloux, M., C. Laurain, M. Weber, and P. H. Hartemann. "Water and nontuberculous mycobacteria." Water Research 33, no. 10 (1999): 2219-2228.
- Fair, Gordon M., J. Carrell Morris, Shih Lu Chang, Ira Weil, and Robert P. Burden. "The behavior of chlorine as a water disinfectant." Journal (American Water Works Association) 40, no. 10 (1948): 1051-1061.
- Hua, Guanghui, and David A. Reckhow. "Comparison of disinfection byproduct formation from chlorine and alternative disinfectants." Water Research 41, no. 8 (2007): 1667-1678.
- Jarroll, Edward L., Alan K. Bingham, and Ernest A. Meyer. "Effect of chlorine on Giardia lamblia cyst viability." Applied and environmental microbiology 41, no. 2 (1981): 483-487.
- Kilvington, Simon, Wayne Heaselgrave, John M. Lally, Kate Ambrus, and Hayes Powell. "Encystment of Acanthamoeba during incubation in multipurpose contact lens disinfectant solutions and experimental formulations." Eye & contact lens 34, no. 3 (2008): 133-139.
- Kiura, Hiromasa, Kouichi Sano, Shinichi Morimatsu, Takashi Nakano, Chizuko Morita, Masaki Yamaguchi, Toyoyuki Maeda, and Yoji Katsuoka. "Bactericidal activity of electrolyzed acid water from solution containing sodium chloride at low concentration, in comparison with that at high concentration." Journal of Microbiological Methods 49, no. 3 (2002): 285-293.
- Lazarova, V., Ph Savoye, M. L. Janex, E. R. Blatchley III, and M. Pommepuy. "Advanced wastewater disinfection technologies: state of the art and perspectives." Water Science and Technology 40, no. 4 (1999): 203-213.
- Plewa, Michael J., Elizabeth D. Wagner, Paulina Jazwierska, Susan D. Richardson, Paul H. Chen, and A. Bruce McKague. "Halonitromethane drinking water disinfection byproducts: chemical characterization and mammalian cell cytotoxicity and genotoxicity." Environmental science & technology 38, no. 1 (2004): 62-68.
- Richardson, S. D., A. D. Thruston Jr, T. V. Caughran, P. H. Chen, T. W. Collette, K. M. Schenck, B. W. Lykins Jr, Ch Rav-Acha, and V. Glezer. "Identification of new drinking water disinfection by-products from ozone, chlorine dioxide, chloramine, and chlorine." In Environmental Challenges, pp. 95-102. Springer Netherlands, 2000.
- Singh, R. P., A. Boucher, and T. H. Somerville. "Evaluation of chemicals for disinfection of laboratory equipment exposed to potato spindle tuber viroid." American Potato Journal 66, no. 4 (1989): 239-245.
- Von Gunten, Urs. "Ozonation of drinking water: Part II. Disinfection and by-product formation in presence of bromide, iodide or chlorine." Water Research 37, no. 7 (2003): 1469-1487.
- Waltimo, T. M. T., D. Ørstavik, E. K. Siren, and M. P. P. Haapasalo. "In vitro susceptibility of Candida albicans to four disinfectants and their combinations." International Endodontic Journal 32, no. 6 (1999): 421-429.
- Ward, N. ROBERT, R. L. Wolfe, and BETTY H. Olson. "Effect of pH, application technique, and chlorine-to-nitrogen ratio on disinfectant activity of inorganic chloramines with pure culture bacteria." Applied and environmental microbiology 48, no. 3 (1984): 508-514.
- Wu, F. M., M. P. Doyle, L. R. Beuchat, J. G. Wells, E. D. Mintz, and B. Swaminathan. "Fate of Shigella sonnei on parsley and methods of disinfection." Journal of Food Protection® 63, no. 5 (2000): 568-572.
- Wu, Wells W., Paul A. Chadik, William M. Davis, Joseph J. Delfino, and David H. Powell. "The effect of structural characteristics of humic substances on disinfection by-product formation in chlorination." In ACS SYMPOSIUM SERIES, vol. 761, pp. 109-121. Washington, DC; American Chemical Society; 1999, 2000.
- Yu-sen, E. Lin, Radisav D. Vidic, Janet E. Stout, and L. Yu Victor. "Negative effect of high pH on biocidal efficacy of copper and silver ions in controlling Legionella pneumophila." Applied and environmental microbiology 68, no. 6 (2002): 2711-2715. Abstract:
Copper-silver (Cu-Ag) ionization has effectively controlled Legionella spp. in the hot water systems of numerous hospitals. However, it was ineffective at controlling Legionella in one Ohio hospital despite the confirmation of adequate total concentrations of copper and silver ions. The pH of the water at this hospital was found to be 8.5 to 9.0. The purpose of this study was to investigate the impact of pH and other water quality parameters, including alkalinity (HCO3−), hardness (Ca2+ and Mg2+), and amount of dissolved organic carbon (DOC), on the control of Legionella by Cu-Ag ionization. Initial concentrations of Legionella and copper and silver ions used in batch experiments were 3 × 106 CFU/ml and 0.4 and 0.08 mg/liter, respectively. Changes in bicarbonate ion concentration (50, 100, and 150 mg/liter), water hardness (Ca2+ at 50 and 100 mg/liter; Mg2+ at 40 and 80 mg/liter), and level of DOC (0.5 and 2 mg/liter) had no significant impact on the efficacy of copper and silver ions in killing Legionella at a neutral pH. When the pH was elevated to 9 in these experiments, copper ions achieved only a 10-fold reduction in the number of Legionella organisms in 24 h, compared to a millionfold decrease at pH 7.0. Silver ions were able to achieve a millionfold reduction in 24 h at all ranges of water quality parameters tested. Precipitation of insoluble copper complexes was observed at a pH above 6.0. These results suggest that pH may be an important factor in the efficacy of copper-silver ionization in controlling Legionella in water systems. - [1]US EPA, "Water: Basic Information about Regulated Drinking Water Contaminants", retrieved 8/27/2013, original source http://water.epa.gov/drink/contaminants/basicinformation/disinfectants.cfm
- [1a] Drinking Water from Household Wells - PDF, U.S. EPA, Original source last retrieved 2/13/2013, original source: http://www.epa.gov/privatewells/pdfs/household_wells.pdf
- [1b] US EPA, "Chlorine Dioxide" (Alternative Water Disinfectants Manual) [PDF] U.S. Environmental Protection Agency
- [2] ATSDR Agency for Toxic Substances Disease Registry, Toxic Substances Portal: Chlorine Toxicity, [PDF] November 2010, retrieved 8/27/2013, original source: www.atsdr.cdc.gov
- [2a]Thanks to reader Jerry Highsmith for discussing well shocking procedures where a water filter or water softener are installed - August 2010
- [3] "Bacteria in Drinking Water" - "Chlorine," Karen Mancl, water quality specialist, Agricultural Engineering, Ohio State University Extension. Mancl explains factors affecting the effectiveness of chlorine in water as a means to destroy bacteria and other microorganisms. OSU reports as follows:
Chlorine kills bacteria, including disease-causing organisms and the nuisance organism, iron bacteria. However, low levels of chlorine, normally used to disinfect water, are not an effective treatment for giardia cysts. A chlorine level of over 10 mg/1 must be maintained for at least 30 minutes to kill giardia cysts. -- http://ohioline.osu.edu/b795/index.html is the front page of this bulletin.
- [5] Canadian BC Ministry of Environment, "Water Stewardship Information Series: When Standard Water Well Chlorination Procedures are Ineffective Fact Sheet developed for Well Drillers, Health Authority Staff and others involved in well recovery efforts after a flood " ", Agriculture and Agri-Food, Canada, retrieved 4/8/2013 original source: http://www.env.gov.bc.ca/wsd/plan_protect_sustain/ groundwater/wells/factsheets/PFRA_well_recovery.pdf
- [5a] "Chemical Cleaning, Disinfection and Decontamination of Water Well" John Schnieders. Johnson Screens Inc. St. Paul, MN
- [5b] Water Well Management Level 2 Training Module. Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada, Alberta Environment, Alberta Water Well Drilling Association and Alberta Agriculture, Food and Rural Development
- [6] Water Wells that last for Generations. Alberta Agriculture, Food and Rural Development; Alberta Environment; Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada
- [7] Water Well Management Level 2 Training Module. Prairie Farm Rehabilitation Administration of Agriculture and Agri-Food Canada, Alberta Environment, Alberta Water Well Drilling Association and Alberta Agriculture, Food and Rural Development
- [8] Chemical Cleaning, Disinfection and Decontamination of Water Wells. John Schnieders. Published by Johnson Screens Inc. St. Paul, MN
- Water Quality Association P.O. Box 606 4151 Naperville Road Lisle, IL 60532 www.wqa.org
- National Sanitation Foundation P.O. Box 130140 789 N Dixboro Road Ann Arbor, MI 48113-0140 (734) 769-8010, (800) NSF-MARK www.nsf.org
- U.S. Environmental Protection Agency (to visit in person) Office of Water Resource Center 1200 Pennsylvania Avenue, NW Ariel Rios Building Washington, DC 20460 Phone: (202) 260-7786, email: center.water-resource@epa.gov
- The Safe Drinking Water Hotline (800) 426-4791 The hotline operates from 9:00 AM to 5:30 PM (EST) The hotline can be accessed on the Internet at www.epa.gov/safewater/drinklink.html
- Water Systems Council www.watersystemscouncil.org
- Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.
- Crystal Clear Supply provides portable ceramic water filter purifiers and portable reverse osmosis water treatment equipment - see http://www.crystalclearsupply.com/category_s/7.htm
- Handbook of Disinfectants and Antiseptics, Joseph M. Ascenzi (Editor), CRC, 1995, ISBN-10: 0824795245 ISBN-13: 978-0824795245 "The evaluation of chemical germicides predates the golden age of microbiology..." -
This well-focused, up-to-date reference details the current medical uses of antiseptics and disinfectants -- particularly in the control of hospital-acquired infections -- presenting methods for evaluating products to obtain regulatory approval and examining chemical, physical, and microbiological properties as well as the toxicology of the most widely used commercial chemicals. - Potable Aqua® emergency drinking water germicidal tablets are produced by the Wisconsin Pharmacal Co., Jackson WI 53037. 800-558-6614 pharmacalway.com
- Principles and Practice of Disinfection, Preservation and Sterilization (Hardcover)
by A. D. Russell (Editor), W. B. Hugo (Editor), G. A. J. Ayliffe (Editor), Blackwell Science, 2004. ISBN-10: 1405101997, ISBN-13: 978-1405101998.
"This superb book is the best of its kind available and one that will undoubtedly be useful, if not essential, to workers in a variety of industries. Thirty-one distinguished specialists deal comprehensively with the subject matter indicated by the title ... The book is produced with care, is very readable with useful selected references at the end of each chapter and an excellent index. It is an essential source book for everyone interested in this field. For pharmacy undergraduates, it will complement the excellent text on pharmaceutical microbiology by two of the present editors."
The Pharmaceutical Journal: "This is an excellent book. It deals comprehensively and authoritatively with its subject with contributions from 31 distinguished specialists. There is a great deal to interest all those involved in hospital infection ... This book is exceptionally well laid out. There are well chosen references for each chapter and an excellent index. It is highly recommended." The Journal of Hospital Infection.: "The editors and authors must be congratulated for this excellent treatise on nonantibiotic antimicrobial measures in hospitals and industry ... The publication is highly recommended to hospital and research personnel, especially to clinical microbiologists, infection-control and environmental-safety specialists, pharmacists, and dieticians."
New England Journal of Medicine: City Hospital, Birmingham, UK. Covers the many methods of the elimination or prevention of microbial growth. Provides an historical overview, descriptions of the types of antimicrobial agents, factors affecting efficacy, evaluation methods, and types of resistance. Features sterilization methods, and more. Previous edition: c1999. DNLM: Sterilization--methods. - In addition to citations & references found in this article, see the research citations given at the end of the related articles found at our suggested
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- Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. Tel: (416) 964-9415 1-800-268-7070 Email: info@carsondunlop.com. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The HOME REFERENCE BOOK - the Encyclopedia of Homes and to use illustrations from The ILLUSTRATED HOME .
Carson Dunlop Associates provides extensive home inspection education and report writing material. In gratitude we provide links to tsome Carson Dunlop Associates products and services.
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